1. Field of the Invention
The present invention relates to an electric power split hybrid system, particularly with regard to an electric power split hybrid system with a switching part. The electric power split hybrid system has advantages and effectiveness of extending battery life and reducing a battery volume to enhance overall fuel economic benefit.
2. The Related Arts
In general, hybrid motorcycles can now be switched to one of two modes of an electric driving mode (by a motor) and a fuel-driven mode (by an engine). Only one of the two modes is utilized to drive motorcycles at one time. Hence, there are still the following disadvantages.
[1] Shorter battery life and larger battery volume. Generally, the battery life is calculated based on times of charging and discharging. In the electric driving mode, electric power of the motor is supplied by the battery completely. Therefore, when the electric driving mode is used more frequently, the number of charging and discharging the battery increases dramatically. As a result, a life of such battery is naturally shortened. Besides, in order to maintain a driving ability for certain distances, the battery in design also needs to have an adequate electrical quantity, and in return, the battery will have a relatively larger volume. Based on a current trend of energy saving in the world, a battery with a short battery life and a larger battery volume is apparently hard to be accepted by the current market.
[2] Lower fuel economy benefit. In general, when an engine is maintained to run under a medium-speed high-efficiency status, its fuel economy benefit can reach the best. However, when ordinary hybrid motorcycles are switched to their fuel-driven mode, the engine drives motorcycles individually, and a rotational velocity of wheels changes together with a rotational velocity of the engine. Therefore, usage of the engine varies based on user's required speeds. A medium-speed high-efficiency status of the engine cannot be maintained all the time, and failure of maintaining results in a lower fuel economy benefit.